What Is Carnot Heat Engine?


3 Answers

Syed Asim Profile
Syed Asim answered
A Carnot heat engine is a hypothetical heat engine which works on the basis of reversible Carnot cycle. It is assumed as the most efficient heat cycle consisting of two isothermal and two adiabatic processes. This is the engine which could be operated at the maximum efficiency.
In the Carnot heat cycle there are four basic steps in the first step the engine absorbs heat and the gas begins to expand. In this step the temperature of the gas does not change and hence it is an isothermal process all the amount of heat energy is used to expand the gas only. In the second step the gas is still expanding but a cooling is being done so this type of process is called adiabatic expanding. In the third step the gas which is cooled in step two is now recompressed and heat goes to the heat sink. In this third stage there is a decrease in volume but an increase in the pressure of the gas however temperature still stays constant so this is an isothermal compression process. In the fourth step the gas cool gas is compressed again and its temperature goes back to the original temperature again a temperature change is observed so this is an adiabatic compression.
Anonymous Profile
Anonymous answered
An Engine which comes back it initial condition after some changes is called CARNOT heat engine. It is an imaginary engine which have max efficiency this engine is free from all hear and friction losses.

CONSTRUCTION:-  A CARNOT heat engine consist of a cylinder having non conducting walls and conducting base. It is provided with piston which is friction less as well as non conductor. A cylinder contains an ideal gas as working substance. This engine may have two bodies at different temperates non as heat source and heat sink.

PRINCIPLE:-   It is based on a cyclic process SA-ADI CARNOT engine take seat from heat sources and converts a parts of this heat into work and gives the remaining heat into heat sink.
Saki Profile
Saki answered
Sadi Carnot in 1840 proposed an ideal heat engine which is free from friction had heat losses. He described it using only isothermal and adiabatic processes. He showed that its efficiency would be maximum when heat engine works in an reversible cycle between two heat reservoirs at different temperatures , but its efficiency cannot be 100%. The efficiency of actual engine is less than that of carnot engine.

Carnot engine works on the same principle as that of cyclic heat engines. All cyclic heat engines absorb some quantity of heat from source , convert a part of heat energy into work and reject the remaining part of the heat to the sink.

Carnot engine consists of a cylinder with non-conducting walls and a conducting base. Ideal gas is enclosed in the cylinder by means of a frictionless and non conducting piston. Two heat reservoirs at fixed temperatures T1 and T2 serve as source and sink.
carnot engine operates in a cycle. This cycle is known as carnot cycle . Consider an engine operating between a source at temperature T1 and sink at temperature T2.Let Q1 and Q2 be the quantity of heat absorbed from and rejected to source and sink respectively.

The carnot engine is placed on a hot reservoir (source) at temperature T1 and the gas is allowed to expand by raising the piston. The cylinder is placed on an insulator and the gas is allowed to expand further adiabatically. The gas cools from temperature T1 to T2.
The engine is then put on a cold reservoir (sink) at temperature T2 and the gas is compressed slowly. During the compression , the temperature of the gas rises but the heat Q2 is rejected by the gas to the sink making the temperature constant at T2. The engine is once again placed on an insulator and the gas is compressed further adiabatically. During this compression , the gas is heated from T2 to T1 so that the gas returns to its original state at T1. As the system has regained its initial state, these four steps complete one carnot cycle.

Answer Question